In order to solve the problem of poor stability of HPAM (partially hydrolyzed polyacrylamide) gel as a plugging agent at 150 °C, this paper investigates the preparation of a polymer gel strengthened with nano-SiO₂, exhibiting good thermal stability, using a low-cost, low-hydrolysis anionic polymer. The experimental results indicated that when the gel was prepared with 1 wt% HPAM, 1 wt% water-soluble phenolic resin (WSPR) as a crosslinker, and 1 wt% nano-SiO₂ as a stabilizer, the dehydration rate of the gel was less than 5 wt% after 180 days of aging at 150 °C. In order to identify the stability mechanism of nano-SiO₂-strengthened polymer gel, we conducted rheological tests, Cryo-SEM analysis, Fourier transform infrared (FTIR) spectroscopy, and solid-state nuclear magnetic resonance (NMR) analysis on the polymer gel before and after adding nanoparticles. The methods described in the study demonstrate the excellent long-term thermal stability of the polymer gel strengthened with nano-SiO₂ from both chemical bonding and microscopic perspectives. The results of rheological experiments indicated that the addition of nanoparticles improved the yield stress and long-term thermal stability of the gel. The scanning electron microscope (SEM) microstructure analysis confirmed that the addition of nanoparticles resulted in high-density cavities between the microscopic network structures of the gel. This facilitated the trapping of a significant amount of free water and the formation of a stable spatial mechanical support structure, ultimately enhancing the macro-mechanical strength of the gel. Additionally, FTIR and NMR experiments demonstrated that the nanoparticles effectively inhibited the hydrolysis of amide groups to carboxylate, thereby significantly preventing the high-temperature degradation of the gel and maintaining its strength after prolonged aging.

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中文翻译：

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纳米粒子增强聚合物凝胶的制备及其耐温机理

针对HPAM（部分水解聚丙烯酰胺）凝胶作为堵漏剂在150 ℃下稳定性差的问题，本文研究了纳米SiO ₂增强聚合物凝胶的制备方法，该凝胶表现出良好的热稳定性，采用较低的热稳定性。 -成本低、水解度低的阴离子聚合物。实验结果表明,以1 wt% HPAM、1 wt%水溶性酚醛树脂(WSPR)为交联剂、1 wt%纳米SiO ₂为稳定剂制备凝胶时,凝胶的脱水率为150°C 老化 180 天后，含量低于 5 wt%。为了明确纳米SiO ₂增强聚合物凝胶的稳定性机理，我们对聚合物凝胶进行了流变测试、冷冻扫描电镜分析、傅里叶变换红外（FTIR）光谱和固态核磁共振（NMR）分析。添加纳米粒子之前和之后。研究中描述的方法从化学键合和微观角度证明了纳米SiO ₂增强的聚合物凝胶具有优异的长期热稳定性。流变实验结果表明，纳米粒子的添加提高了凝胶的屈服应力和长期热稳定性。扫描电子显微镜（SEM）微观结构分析证实，纳米颗粒的添加导致凝胶微观网络结构之间产生高密度空腔。这有利于捕获大量的自由水并形成稳定的空间机械支撑结构，最终增强凝胶的宏观机械强度。此外，FTIR和NMR实验表明，纳米粒子有效抑制酰胺基团水解为羧酸盐，从而显着防止凝胶的高温降解并在长时间老化后保持其强度。

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